Competitive solid phase enzyme-linked immunoassay for the quantification of limonin in citrus

A solid-phase enzyme immunoassay for the quantitative determination of the bitter triterpenelactone, limonin, in citrus juice samples is described. As little as 0.1 ppm of limonin can be detected. Quantitative results are available within 1 h of total assay time. The assay makes use of a limonin-alkaline phosphatase tracer of high immunoreactivity and has been semiautomated using antibody-coated polystyrene microcuvettes, a vertical light path photometer, and a forcedair microplate incubator.